Eating fish helps control diabetes

Adding fish to the dinner menu twice a week may lower the risk of kidney disease in people with diabetes, according to a study published in the November issue of American Journal of Kidney Diseases, the official journal of the National Kidney Foundation.

“Diet is a relatively simple lifestyle change to make and the benefits could be significant,” says Dr Amanda Adler, co-investigator Amanda Adler at the Medical Research Council Epidemiology Unit, at the Institute of Metabolic Science in Cambridge.

The research team studied more than 22,000 middle-aged and older men and women, 517 of whom had diabetes. Fish consumption was determined using dietary and lifestyle questionnaires. Participants with diabetes who on average ate less than one serving of fish per week were four times more likely to have macroalbuminuria, or protein in the urine, than those who ate at least two servings per week. 18 percent of those with low fish consumption had macroalbuminuria, versus four percent of those who regularly included fish in their diet. Dr Adler noted that people who eat fish may differ in other ways that lessen their chance of having albuminuria, but that the study attempted to account for this possibility.

Albuminuria means that the kidney has some damage and is starting to spill protein into the urine, and is an early sign of diabetic kidney disease. Individuals with macroalbuminuria spill more protein than those with microalbuminuria.Kidney disease is one of the most serious complications of diabetes. In addition to albuminuria, after years of diabetes, the filtering units of the kidney may scar and cannot clean the blood efficiently. Eventually, the kidneys may fail completely so that a person with the disease needs dialysis or a kidney transplant. Albuminuria increases the risk of renal failure and is also tied to higher rates of heart disease.

Dr. Adler said “The unique nutrient composition of fish may exert its beneficial effects on kidney function by enhancing blood glucose control and improving plasma lipid profiles. Combined with tight control of glucose, this may be an effective dietary method to lower the risk of albuminuria. Other measures are keeping blood pressure under control, quitting cigarette smoking and losing weight, if needed.” Professor Nick Wareham, co-director of the Institute for Metabolic Science (IMS) and Director of the MRC Epidemiology Unit, said: “This research contributes to the wealth of evidence that simple lifestyle changes can help prevent chronic conditions such as diabetes and its complications. Research at the IMS demonstrates that better understanding of disease can help us achieve better treatments and preventive interventions.”

(Source: Medical Research Council: American Journal of Kidney Diseases: November 2008.)